Thai police said former PetroSaudi International director Xavier Andre Justo, who allegedly stole the company's information and sold them to third parties, had denied tampering the documents.
"He didn't make any changes to the documents and sent the original documents (to the buyer) as digital copies," Royal Thai Police Commissioner of Officer of Information and Communication Technology Lt Gen Prawut Thavornsiri was quoted as saying by New Straits Times (NST).
He said Justo also admitted to blackmailing PetroSaudi using the thousands of emails and documents allegedly stole from the company.
Justo, who was arrested last month, will be charged under Thai law for extortion and blackmail.
According to Thai police, Justo had demanded for 2.5 million Swiss francs (RM9.9 million) in exchange for not revealing the information he allegedly stole.
Asked by NST if the information was sold to Sarawak Report , Prawut replied: "Everyone knows which news organisation I am talking about."
The PetroSaudi information sold by Justo had put 1MDB in a spot as it included email correspondence between PetroSaudi and 1MDB.
The information in the emails was used as a basis by Sarawak Report to allege misappropriation of 1MDB's funds.
It claimed that 1MDB's funds intended for a joint venture with PetroSaudi was siphoned into a company controlled by billionaire Jho Low, who is close to Prime Minister Najib Abdul Razak's family.
The government had insisted the information was tampered with based on an analysis by cyber security expert Protection Group International, which was hired by PetroSaudi to investigate its leaked information.